import urllib
import urllib2

url = 'http://grubbn.com/fluxbb/post.php?tid=180'

values = {
# req_username, req_email, req_message
# Guest name:, Guest e-mail:, Write message:
# form_sent, forum_user
# Guest, 1
'req_username' : 'Grubbot',
'req_email' : 'nathangrubb@grubbn.com',
'req_message' : 'this is a test message from a bot'
 }

data = urllib.urlencode(values)
resp = urllib2.urlopen(url, data)

print resp.read()  